WASHINGTON
— The Pentagon says it will start running out of money for the war in Iraq by early May. But as the Senate took up an $80 billion emergency funding measure for US military efforts, debate on the floor last week turned to the need to raise quotas for seasonal workers to shuck oysters for the seafood industry.

It's one sign of how politically sensitive policies on immigration are now coming to the forefront - and exposing rifts within the Republican Party.

After months of stalling a debate on immigration, President Bush and GOP leaders in Congress now must face the divisive issue on several fronts, from proposals for tighter policies on driver's licenses to allowing more guest workers into the US.

Whether the goal is getting tougher or more flexible, policymakers are confronted with difficult choices involving national security, economics, and the the rising prominence of Hispanic Americans in the nation's politics.

For Republicans, who now control both ends of Pennsylvania avenue, immigration has long been an especially divisive issue. Many conservatives see the presence of some 8 million to 12 million undocumented immigrants as a serious breach of the rule of law as well as a burden to states and localities paying the cost of providing education and health services for them. "What part of 'illegal' don't you understand?" is the mantra for the get-tough wing of the party.

At the same time, President Bush's success in winning over Hispanic voters is reinforcing calls for a historic shift in the GOP stance on immigration. In early 2004, the president outlined principles for comprehensive immigration reform, including a guest-worker program and a path to legality for undocumented workers already in the country.

A recent poll by Republican consultant Ed Goeas signals that some 25 percent of voters support such a plan, 25 percent oppose it, and 50 percent are undecided. Some 80 percent of voters say it's unrealistic to deport some 10 million illegals.

"The fight now is to win over that 50 percent," says Tamar Jacoby, a senior fellow at the Manhattan Institute, who is making the case for reform to conservatives. "In the past, the debate over immigration was about open borders or closed, high numbers or low. We're now seeing a new middle in the Republican Party that recognizes that immigrants are good for the country, but that we need to bring them here in a controlled manner that enhances our security."

Indeed, neither major party wants to be cast as anti-immigrant, especially in an era of growing Hispanic clout.

Still, concern about porous borders rankles many Americans - symbolized by the mobilization of volunteer "minutemen" to patrol a portion of the Arizona border this month.

The immigration issue almost derailed last year's overhaul of the nation's intelligence agencies, until the White House helped cut a deal with House conservatives to pull controversial border-control provisions. The deal provided that the provisions could be voted on in the first must-pass bill in the 109th Congress. With the Defense supplemental bill for Iraq, that marker comes due.

The House provisions, which include national standards for driver's licenses, tougher asylum requirements, and waiver authority to complete projects such as a fence on the US-Mexico border, face strong opposition in the Senate on both sides of the aisle, as well as from civil liberties and pro-immigration groups.

Some senators are opposed especially to any move that requires states to verify the legal status of applicants for driver's licenses. Others, including Sen. Barbara Mikulski (D) of Maryland who proposed the seasonal-worker amendment, don't want to see the House version of border control pass into law without the Senate taking up its own priorities on immigration.

The Mikulski amendment opened the door to a flood of immigration amendments. Sen. Larry Craig (R) of Idaho is proposing a path to legal status for agricultural workers. Others are preparing more comprehensive immigration proposals that they do not want to see preempted by the House bill.

In a 61-38 vote last week, the Senate called for dropping all immigration provisions from the fiscal 2005 defense supplemental spending bill - a move calculated to boost the Senate negotiators in conference with their House counterparts. After failing to persuade senators to back off such amendments, Senate majority leader Bill Frist set up votes Tuesday to limit debate on these immigration proposals and hasten passage of the defense bill. "Congress should not delay enactment of critical appropriations necessary to ensure the well-being of our men and women in uniform," said Sen. John Cornyn (R) of Texas, who proposed the amendment. "Attempting to conduct a debate about immigration reform while the supplemental appropriations bill is pending in the Senate would do just that."

Indeed, the battle over immigration may not be easy for Republicans, whenever it occurs.

"There's a general feeling among most Republicans that any kind of an amnesty program would be questionable simply because it would encourage more illegal immigration and reward people who have broken the law," says Rep. Lamar Smith (R) of Texas, a longtime opponent of amnesty.

Many in the GOP criticize the president for not taking a harder line.

Commenting on the volunteers along the Arizona border to stop illegal immigration, freshman Sen. Tom Coburn (R) of Oklahoma added: "The president calls them vigilantes. It seems to me that shows that he just doesn't get it."

A Senate hearing on immigration enforcement painted a stark picture last week: Some 80 to 85 percent of people facing deportation orders don't comply, and of the more than 400,000 names of fugitives, less than 10 percent have been entered into federal crime databases.